Referring to FIG. 11, a structure of a pulsator type washing machine which is one of the representative washing systems is explained in the following.
As illustrated in FIG. 11, an outer tank 30 contains a washing spin tank 32 on the bottom of which a pulsator 31 is rotatably disposed, and is suspended with plurality of suspension rods 33 from an outer frame 34 of a washing machine. A motor 35 drives the pulsator 31 or the washing spin tank 32 via a V-belt 36 and a speed-reduction mechanism and clutch 37. A drain valve 38 is for draining washing water from inside the washing spin tank 32 which is provided with a multiplicity of holes on its outer wall, while a water supply valve 39 is for supplying water into the washing spin tank 32.
A fluidic balancer 40 is provided on an upper part of the washing spin tank 32 to reduce vibration during spin drying, and a lid 41 is disposed above it. A control apparatus 42 successively controls each of the washing, rinsing, and spin-drying processes by controlling the motor 35, the drain valve 38, and the water supply valve 39, etc.
Action of the above structure is next described. Upon starting washing after putting a wash and a predetermined quantity of detergent into the washing spin tank 32, the water supply valve 39 is controlled by the control apparatus 42 and a predetermined quantity of water is supplied into the washing spin tank 32; subsequently, the control apparatus 42 controls the motor 35 to rotate the pulsator 31. The wash and water inside the washing spin tank 32 are stirred by the rotation of the pulsator 31, and this stirring gradually causes the detergent to dissolve, producing washing water which acts on the dirt of the wash.
However, in a washing machine of this structure, it is general practice to stir the wash and water by rotating the pulsator 31 at a high speed in order to dissolve the loaded detergent. In this case, in order to keep the wash insulated from excessive mechanical force, stirring by the pulsator 31 used to be started after a predetermined quantity of water has been supplied to the washing spin tank 32.
In other words, the time spent during supplying water does not have any benefit from the standpoint of removal of dirt because stirring by the pulsator 31 is not started until a predetermined quantity of water has been supplied. Also, since the supplied water penetrates into the wash as it is, a certain period of time is required until the detergent, which had started to dissolve with the start of the stirring, penetrates into the entire wash and comes to a uniform concentration required for the removal of dirt, again spending idle time from the standpoint of removal of dirt.
From the standpoint of damage of the wash, too, it is inefficient to start the stirring by the pulsator 31 from a state in which the detergent is not fully acting on the wash. That is, when the wash is stirred in a state in which the detergent has not penetrated into the wash, a large frictional force is applied to the surface of the wash, presenting problems of damaging the wash, such damage including napping of the surface.